Federal agents expressed concern that Christopher Dorner was fleeing to Mexico, hours after shooting and killing a Riverside police officer, according to a court affidavit filed last week.

While the search for Dorner has focused on the Big Bear area, where his burning truck was found Thursday, patrols have also been increased near the Mexican border.

U.S. Customs and Border Protection agents have stepped up their inspections at the San Ysidro border crossing into Tijuana, and Mexican officers have been given photographs of Dorner, with a warning to consider him armed and extremely dangerous, The Associated Press reported on Monday.

A hotel in Tijuana was raided early Monday in search of Dorner, the San Diego Reader reported. More than 20 officers searched the Hotel Tapatio, which is located about 250 meters from the U.S. border, the publication's website reported, but no evidence of Dorner was found.

A federal court affidavit filed by a U.S. Marshals Service inspector on Thursday noted that a wallet and identification cards belonging to Dorner were found Thursday near the San Ysidro crossing.

The complaint, signed Thursday by a U.S. magistrate judge in Orange County, charges Dorner with fleeing the country to avoid prosecution, suggesting that even as hundreds of officers have spent days searching for him, he might already be out of the country.

Authorities have said there is no indication now that he is in Mexico. But they have not had any confirmed sightings of him since he engaged in shootouts with police in Corona and Riverside early Thursday morning, killing one officer.

The court affidavit also reveals how authorities found Dorner's burning truck in San Bernardino.

The affidavit is supposed to show there is sufficient cause for an arrest warrant and a criminal complaint against Dorner.

In the affidavit, Inspector Craig McClusky of the U.S. Marshal Service wrote there was probable cause to believe Dorner has moved and traveled from California to Mexico with the intent to avoid prosecution.

McClusky referred to the Feb. 7 incident in San Diego where Dorner allegedly tried to steal a boat and told the victim he was taking the boat to Mexico.

He added that a guard at the Point Loma naval base in San Diego reported later that day seeing a man matching Dorner's description trying to gain access to the base.

According to the same affidavit, the marshals had also been tracking a known associate identified only as "J.Y."

He wrote that a family member of J.Y. owns residential property in Arrow Bear. The marshals and the San Bernardino County Sheriff's deputies were doing surveillance of the property at 12:45 p.m. Thursday when they found a gray 2005 Nissan Titan on fire. It was later identified as Dorner's pickup.

Quan is the daughter of retired LAPD captain Randal Quan, who represented Dorner at his 2008 internal trial before his firing.

In a lengthy Facebook post, Dorner threatened revenge on LAPD officers he believes wronged him, as well as the officers' families. He accuses Quan of not representing his interests.

According to the court affidavit, on Thursday afternoon a man identified in the document as R.Q. - apparently Randal Quan - got a call from a man identifying himself as Dorner, who told Quan he "should have done a better job of protecting his daughter."

The phone call was traced to Vancouver, Wash., but authorities don't believe Dorner was actually in Washington state at the time.

Police officials on Monday said they believe the call was a prank.

A Marshals Service spokeswoman couldn't be reached for comment Monday.

The affidavit by Inspector Craig McClusky gives new details of the timeline authorities have been able to piece together of Dorner's apparent movements Thursday.

After firing on two LAPD officers about 1:30 a.m. in Corona, slightly injuring one, he shot two Riverside police officers in Riverside about 2 a.m., killing one, the marshals believe.

About 3 a.m., the affidavit says, he tried to steal a boat from a captain in San Diego, identified as C.C.

"C.C. reported that at approximately 3:00 A.M. today, a man matching Dorner's description had subdued him and tried to steal his boat, stating that he (Dorner) would be taking the boat to Mexico, and that C.C. would be able to recover the boat there," McClusky wrote.

But the bow line got caught in the propeller, and Dorner fled, the affidavit says.